Thorny trunk-like structure of reduced graphene oxide/HKUST-1 MOF for enhanced EMI shielding capability

Abstract

A composite of reduced graphene oxide (rGO) coated with metal-organic framework (MOF) HKUST-1 was synthesized using a facile hydrothermal method. The micro-frame of HKUST-1 was retained with the well-decorated octahedral framework on the surface of rGO sheets, resulting in the production of a scabrous, thorny trunk structure. The as-prepared composites exhibited the best shielding effectiveness at a weight ratio of 1:1 of the rGO:Cu(NO3)2.3H2O precursor, with a total shielding value (SET) greater than 36 dB over a wide frequency range (i.e., from 8.2 to 18 GHz). The maximum SET of the composite exceeded 46.1 dB at 18 GHz, compared to a value of 36.6 dB in pristine rGO. The introduction of the HKUST-1 MOF, which was anchored to the surface of rGO, prevented sheet layers from aggregating and decreased the impedance mismatching by limiting the value of shielding effectiveness by reflection. The mechanism of electromagnetic shielding was attributed mainly to dielectric loss and synergic effects between rGO and HKUST-1.